Using Kirchhoff's laws for multiple batteries and resistors

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Homework Help Overview

The discussion revolves around a circuit problem involving multiple batteries and resistors, specifically focusing on the application of Kirchhoff's laws to determine the current in a specific wire within the circuit setup.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to verify their circuit setup and equations for finding the current in the third wire. Some participants question the accuracy of the circuit diagram and suggest modifications to improve clarity. Others discuss the implications of these changes on the equations derived from the circuit.

Discussion Status

The discussion has seen constructive feedback regarding the circuit diagram, with some participants affirming the correctness of the original equations after reevaluation. There is an ongoing exploration of how the adjustments to the diagram may affect the interpretation of the problem.

Contextual Notes

Participants are navigating issues related to the depiction of connections in the circuit, which may influence the accuracy of the equations derived. There is an emphasis on ensuring that the circuit representation aligns with the theoretical framework of Kirchhoff's laws.

Bolter
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Homework Statement
See full question below
Relevant Equations
Kirchhoff 1st and 2nd law
Hey everyone!

Had an attempt at this circuit question, but wanted to check if I got the set up right in order to find the current in the 3rd wire?
Screenshot 2020-04-21 at 12.55.10.png


Here is what I have done
IMG_4655 2.JPG


Thanks!
 
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You have done well, showing the internal resistance in each battery as an explicit external resistor in series.

However, there is a problem with the depiction of the "mid-point" connections. The three ohm wire connects at the midpoints of the two ohm and the four ohm wires. It would be best to split the two ohm "resistor" at its midpoint and to do the same for the four ohm "resistor".

Because the drawing is misleading, the equations you constructed from it are not correct.
 
Last edited:
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jbriggs444 said:
You have done well, showing the internal resistance in each battery as an explicit external resistor in series.

However, there is a problem with the depiction of the "mid-point" connections. The three ohm wire connects at the midpoints of the two ohm and the four ohm wires. It would be best to split the two ohm "resistor" at its midpoint and to do the same for the four ohm "resistor".

Because the drawing is misleading, the equations you constructed from it are not correct.

So would this be a much preferred circuit diagram then?

IMG_4659.JPG


I think my loop equations will be the same as before if I use Kirchhoff's law on left & right loop
 
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Very nice drawing. And now that I look again your equations were correct to start with.
 
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